View image without any interface
actually the whole interface can be removed from ANY view, not only the Image Editor. Place your mouse cursor over the area in question, then hit Right Alt+F10 (maximize view and remove interface) and then Alt+F11 (remove title bar and also task bar on Windows or dash on Linux). To get back, you can use the same keystrokes, or move the mouse cursor in the top right corner of the window, until an icon appears.